A recent innovation within the field of integrated circuit technology is resistive-switching memory. While much of resistive-switching memory technology is in the development stage, various technological concepts for resistive-switching memory have been demonstrated by the assignee of the present invention and are in one or more stages of verification to prove or disprove associated theory (ies). Even so, resistive-switching memory technology promises to hold substantial advantages over competing technologies in the semiconductor electronics industry.
Resistive random access memory (RRAM) is one type of resistive memory. The inventor believes RRAM has the potential to be a high density non-volatile information storage technology for higher density semiconductor-based devices. Generally, RRAM stores information by controllably switching among distinct resistive states. One theoretical example of an RRAM device includes an insulator layer provided between a pair of electrodes. Such a device properly configured can exhibit electrical pulse-induced hysteretic resistance switching effects.
Resistance switching is explained (in some theories) as a result of formation of a conductive structure within an otherwise electrically insulating medium. The conductive structure could be formed from ions in a nearby electrode, for instance, having free ions. In some theories, field-assisted diffusion of ions can occur in response to a suitable electric potential or current applied to an RRAM memory cell. According to other theories, filament formation can occur in response to joule heating and electrochemical processes in binary oxides (e.g., NiO, TiO2, or the like), or by a redox process for ionic conductors including oxides, chalcogenides, polymers, and so on.
The inventors expect resistive devices based on an electrode, insulator, electrode model, including those formed on polysiliconto exhibit good endurance and life cycle. Further, the inventors expect such devices to have very high on-chip densities. Accordingly, resistive elements may be viable alternatives to metal-oxide semiconductor (MOS) transistors employed for digital information storage. The inventors of the subject patent application, for instance, believe that models of resistive-switching memory devices provide some potential technical advantages over non-volatile FLASH MOS devices.
In light of the above the inventors desire to make further improvements in memory technology, and resistive memory.